Add flake, for real

flake.nix

@@ -0,0 +1,33 @@
+{
+  description = "Fudo Backplane Client.";
+
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixos-22.05";
+    helpers.url = "git+https://git.fudo.org/fudo-public/nix-helpers.git";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { nixpkgs, helpers, utils, ... }:
+    utils.lib.eachDefaultSystem (system:
+      let pkgs = nixpkgs.legacyPackages."${system}";
+      in {
+        packages = rec {
+          default = fudoBackplaneClient;
+          fudoBackplaneClient = import ./package.nix { inherit pkgs helpers; };
+        };
+
+        devShells = rec {
+          default = update;
+          update = let
+            update-deps = pkgs.writeShellApplication {
+              name = "update-deps";
+              runtimeInputs = with pkgs; [ bundle bundix ];
+              text = ''
+                bundle lock
+                bundix
+              '';
+            };
+          in pkgs.mkShell { buildInputs = with pkgs; [ update-deps ]; };
+        };
+      });
+}